The invention relates to hinges. It is particularly, but not exclusively, related to hinges used in electronic devices. In one embodiment, it relates to hinges used in portable electronic devices.
Many types of electronic devices are known. Portable electronic devices include mobile telephones, personal digital assistants (PDAs) and portable computers such as laptops. As technology improves, it is desired to include more functions in such devices. These functions may include messaging, for example e-mails and SMS (short message service), and entry of various types of information which are useful for a user to be able to access, such as address and calendar information. To provide access to these functions, the devices often comprise user interfaces such as displays and full alphanumeric keyboards or touch-sensitive screens.
It may not be necessary for the complete user interface to be available all of the time. Therefore, some of these devices are foldable so that at least part of the user interface can be stored away when it is not required. In the case of a laptop, it is typically provided in a two-part form connected by hinges having a display in one part and a keyboard in another part. In the case of a multi-function device such as a combined mobile telephone/PDA, there are occasions when a full alpha-numeric keyboard is needed, for example when composing messages or editing text, and other occasions when it is not needed, for example when it is being used as a telephone. An example of such a device is the Nokia(copyright) 9110 Communicator.
FIG. 1 shows a prior art mobile device 10. The mobile device 10 comprises a body part 12 and a cover part 14 which are moveable between a configuration in which the mobile device is open (unfolded) and a configuration in which the mobile device is closed (folded). The body part 12 and the cover part 14 are connected by a pair of hinges 16. The body part 12 comprises necessary control electronics to enable the mobile device 10 to carry out telephony and PDA functions and, on an inner surface which faces the cover part 14 when the mobile device 10 is closed, a full keyboard. The keyboard is used in operation of the mobile device 10 as a PDA and in other operations. The cover part 14 comprises a conventional telephone interface on an outer surface and, on an inner surface which faces the body part 12 when the mobile device 10 is closed, a display. The cover part also comprises an antenna for transmission and reception of radio signals.
Since these devices are usually opened to present a user interface to a user, it is convenient if they can be held open at one or more particular angular configurations. To provide this ability, hinges are used having a suitable stiffness to resist rotation. It is difficult to maintain this ability after thousands or even tens of thousands of openings since wear tends to reduce the stiffness. Although it is possible to provide additional locking means to hold the device in any desired angular configuration (including locking the device in a closed configuration), having such locking means requires additional parts which results in additional weight and space. This is often not desirable since these devices are typically portable and should be lightweight and compact.
The hinge 16 used in the device 10 is shown in FIG. 2. The hinge 16 comprises a first hinge pin element 220 attached to the body part 12 and a second hinge pin element 221 attached to the cover part 14. The hinge pin elements are fixed against rotational movement relative to their respective parts. The first hinge pin element 220 and part of the second hinge pin element 221 are contained in a common hinge pin housing (not shown). An end 222 of the first hinge pin element 220 is provided with a tab 223 and an end 224 of the second hinge pin element 221 is provided with a slot 225. The hinge pin elements abut at their respective ends so that the tab 223 is received in the slot 225. The first hinge pin element 220 is spring-biased by a spring 226 so that the tab 223 is pressed into the slot 225. This keeps the body part 12 and the cover part 14 held relatively to each other.
When the cover part 14 and the body part 12 are moved about the hinge 16 relatively to each other, the tab 223 is forced out of the slot 225, the first hinge pin element 220 moves against its spring-biasing and the hinge pin elements rotate relatively to each other.
According to a first aspect of the invention there is provided a hinge comprising a shaft part and a housing part, the parts being relatively moveable about a common axis of rotation, the shaft part having a first portion lying on the common axis of rotation, the first portion carrying a bearing surface, and a second portion extending radially beyond the bearing surface of the first portion, the housing part having an engagement surface and a hinge surface, the hinge surface cooperating with the bearing surface of the first portion and the engagement surface engaging with the second portion to restrain the shaft part from rotational movement, the shaft part being moveable relative to the housing part between a first position in which the second portion is engaged with the engagement surface and a second position in which the second portion is not engaged with the engagement surface.
In a hinge according to the invention, it is not necessary to provide separate parts, such as a latch, to provide a locking function since this is provide by the interrelation between the shaft part and the housing part. Therefore, the hinge can be provided in a miniature form relatively straightforwardly.
Preferably the bearing surface is spaced apart from the common axis of rotation in radial directions. Preferably different parts of the bearing surface are spaced from the common axis of rotation by the same distance. In this case, the first portion has a round cross-section.
Preferably the second portion extends laterally with respect to the common axis of rotation.
Preferably the hinge surface encloses the first portion. Preferably the hinge surface does not enclose the second portion. Preferably the hinge surface does not enclose the engagement surface.
Preferably, in the second position, the shaft part is not restrained from rotational movement. Preferably in this position the first portion is acted upon by a biasing force in a first direction parallel to the common axis of rotation. Preferably in moving from the first position to the second position, the second portion is displaced axially in a second direction opposite to the first direction.
Preferably the first portion and the second portion meet at a junction and are disposed in an angular relationship. Most preferably, they are disposed at right angles to each other. This disposition may not be exactly equal to 90xc2x0. It may be slightly more or slightly less. It may vary as the shaft part and the housing part move relatively to each other. In another embodiment, the first portion and the second portion meet at an acute or an obtuse angle. Preferably the first and second portions are integrally formed. They may comprise a bent wire. A wire can be bent easily to fit into small hinges. Clearly, this is also inexpensive.
Preferably the shaft part comprises spring biasing means to provide the biasing force. Preferably the biasing force is provided by energy stored when the first and second portions are moved relatively to each other. Preferably the hinge surface does not enclose the spring biasing means.
Preferably the shaft part comprises a pair of first portions. Preferably the shaft part comprises a pair of second portions. The second portions may be substantially parallel. Preferably the second portions are connected together by a connecting portion. Preferably the first portions extend from the second portions away from each other. Alternatively the first portions extend from the second portions towards each other. The second portions may lie on the same axis. They may both lie on the common axis of rotation.
Preferably the housing part comprises a pair of hinge surfaces. Each of the hinge surfaces may co-operate with the bearing surfaces of the pair of the first portions.
Each hinge surface may be associated with a pair of engagement surfaces. This pair of engagement surfaces may be provided to restrain the second portion at two separate angular orientations of the shaft. The angular orientations may be separated by an angular separation of 120xc2x0. Alternatively, the angular separation may be another value such as 90xc2x0 or 180xc2x0. Each hinge surface may be associated with more than two engagement surfaces to provide more than two restraining angular orientations.
Preferably the or each engagement surface has a profile which is complementary to that of a least a part of the bearing surface of the first portion which it restrains. Alternatively, the profile is not complementary so that there is limited contact between the or each engagement surface and the first portion. The or each engagement surface may be provided by a groove having a pair of walls and a bottom. The or each engagement surface may comprise a wall of the groove. In this embodiment, restraining of the shaft part occurs by the first portion being pressed into the groove by the biasing force. In order for the shaft part to move rotationally, the first portion needs to move out of the groove. The depth of the groove may determine the amount of restraining force provided by engagement between the engagement surface and the first portion. A deeper groove may provide a greater restraining force. The angle of the groove wall may determine the amount of restraining force provided to the first portion. The restraining force may be determined by factors such as the length or the thickness of the second portion.
According to a second aspect of the invention there is provided an electronic device comprising a first body element and a second body element connected by a hinge according to the first aspect of the invention.
The hinge may enable the body elements to move relatively to each other so that the device may be opened and closed. Preferably the shaft part is fixed to one body element and the housing part is fixed to another body element.
Preferably the device is portable. Preferably the device is selected from a group consisting of a mobile station, a mobile telephone, a mobile communicator, a personal digital assistant or a mobile computer such as a laptop.